GABA levels in CSF of patients with psychiatric disorders.

The authors measured gamma-aminobutyric acid (GABA) levels in the lumbar CSF of patients with depression, with psychosis, or undergoing evaluation for a neurologic disorder. GABA levels in the CSF from depressed patients were significantly decreased compared with neurologic control patients. CSF GABA levels in psychotic patients were not different from those in neurologic patients, although the data suggested a decrease in CSF GABA levels in patients with schizoaffective disorder.